Prenatal Cannabis Use Linked to Preterm Birth and Birth Defects in 1.28 Million Canadian Births
In a cohort of 1.28 million births across three Canadian provinces, prenatal cannabis use was associated with significantly increased risks of preterm birth, low birth weight, and major congenital anomalies.
Quick Facts
What This Study Found
Prenatal cannabis use (prevalence ~2%) was associated with increased risks of spontaneous preterm birth (aOR 1.80), medically indicated preterm birth (aOR 1.94), very preterm birth (aOR 1.73), low birth weight (aOR 1.90), small-for-gestational age (aOR 1.21), major congenital anomalies (aOR 1.71), cesarean section (aOR 1.13), and gestational diabetes (aOR 1.32). Female infants showed increased susceptibility for SGA and spontaneous preterm birth.
Key Numbers
1,280,447 births; ~2% cannabis prevalence; spontaneous preterm aOR 1.80; medically indicated preterm aOR 1.94; very preterm aOR 1.73; low birth weight aOR 1.90; congenital anomalies aOR 1.71; gestational diabetes aOR 1.32
How They Did This
Population-based retrospective cohort of 1,280,447 singleton births from three Canadian provincial registries (British Columbia, Ontario, Newfoundland/Labrador) from April 2012 to March 2019. Logistic regression adjusted for other substance use, sociodemographic factors, and comorbidities.
Why This Research Matters
This is one of the largest studies ever to examine prenatal cannabis outcomes, spanning nearly 1.3 million births across multiple provinces with adjustment for important confounders including other substance use.
The Bigger Picture
With cannabis legalization in Canada, this massive cohort provides some of the strongest population-level evidence that prenatal cannabis use carries meaningful risks for multiple birth outcomes.
What This Study Doesn't Tell Us
Cannabis use may be underreported. Cannot distinguish frequency, quantity, or method of cannabis use. Residual confounding possible despite statistical adjustment.
Questions This Raises
- ?Why do female infants show greater susceptibility to some cannabis-related outcomes?
- ?Does the timing of cannabis use during pregnancy (first vs third trimester) affect risk differently?
Trust & Context
- Key Stat:
- 1.28 million births studied across 3 provinces
- Evidence Grade:
- Very large population-based cohort across multiple provinces with adjustment for key confounders. One of the largest prenatal cannabis studies to date.
- Study Age:
- Published in 2022
- Original Title:
- Cannabis use in pregnancy and maternal and infant outcomes: A Canadian cross-jurisdictional population-based cohort study.
- Published In:
- PloS one, 17(11), e0276824 (2022)
- Authors:
- Luke, Sabrina, Hobbs, Amy J, Smith, Michaela, Riddell, Catherine, Murphy, Phil, Agborsangaya, Calypse, Cantin, Christina, Fahey, John, Der, Kenny, Pederson, Ann, Nelson, Chantal
- Database ID:
- RTHC-04021
Evidence Hierarchy
Looks back at existing records to find patterns.
What do these levels mean? →Frequently Asked Questions
How much does prenatal cannabis increase preterm birth risk?
This study found prenatal cannabis use nearly doubled the risk of spontaneous preterm birth (aOR 1.80) and medically indicated preterm birth (aOR 1.94) in a cohort of 1.28 million Canadian births.
Does prenatal cannabis cause birth defects?
The study found a 71% increased risk of major congenital anomalies (aOR 1.71) associated with prenatal cannabis use, though the observational design means it cannot definitively prove causation.
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Cite This Study
https://rethinkthc.com/research/RTHC-04021APA
Luke, Sabrina; Hobbs, Amy J; Smith, Michaela; Riddell, Catherine; Murphy, Phil; Agborsangaya, Calypse; Cantin, Christina; Fahey, John; Der, Kenny; Pederson, Ann; Nelson, Chantal. (2022). Cannabis use in pregnancy and maternal and infant outcomes: A Canadian cross-jurisdictional population-based cohort study.. PloS one, 17(11), e0276824. https://doi.org/10.1371/journal.pone.0276824
MLA
Luke, Sabrina, et al. "Cannabis use in pregnancy and maternal and infant outcomes: A Canadian cross-jurisdictional population-based cohort study.." PloS one, 2022. https://doi.org/10.1371/journal.pone.0276824
RethinkTHC
RethinkTHC Research Database. "Cannabis use in pregnancy and maternal and infant outcomes: ..." RTHC-04021. Retrieved from https://rethinkthc.com/research/luke-2022-cannabis-use-in-pregnancy
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.